Not applicable.
In view of the dangers associated with automobile travel, there is an ongoing need for enhanced driver awareness. One possible area of increased driver awareness involves detection of objects around a vehicle. As the vehicle approaches objects (e.g. other cars, pedestrians and obstacles) or as objects approach the vehicle a driver cannot always detect the object and perform intervention actions necessary to avoiding a collision with the object. For example a driver of a vehicle may not be able to detect an object in the so-called xe2x80x9cblind spotxe2x80x9d of the vehicle.
To reduce the number of truck accidents, for example, sensor systems or more simply xe2x80x9csensorsxe2x80x9d for detecting objects around a truck have been suggested. Such sensors typically include an optical or infrared (IR) detector for detecting obstacles in the path of the vehicle.
In such an application, it is necessary to provide a sensor capable of accurately and reliably detecting objects in the path of the vehicle.
Radar is a suitable technology for implementing a sensor for use in vehicles such as automobiles and trucks. One type of radar suitable for this purpose is Frequency Modulated Continuous Wave (FMCW) radar. In typical FMCW radar, the frequency of the transmitted CW signal linearly increases from a first predetermined frequency to a second predetermined frequency. FMCW radar has the advantages of high sensitivity, relatively low transmitter power and good range resolution.
Aspects of the sensors which contribute to its accuracy and reliability include its susceptibility to noise and the overall precision with which received radio frequency (RF) signals are processed to detect objects within the field of view of the sensor. Susceptibility to noise for example can cause false detections and, even more deleteriously, cause an object to go undetected.
Further significant attributes of the sensors are related to its physical size and form factor. Preferably, the sensor is housed in a relatively small enclosure or housing mountable behind the a surface of the vehicle. For accuracy and reliability, it is imperative that the transmit and receive antenna and circuitry of the sensor are unaffected by attributes of the vehicle (e.g. the vehicle grill, bumper or the like) and that the sensors are mounted to the vehicle in a predictable alignment.
It would, therefore, be desirable to provide a sensor system which is capable of detecting objects all around a vehicle. It would also be desirable to provide a system which can be adapted to provide detection zones around vehicles of different sizes. It would be further desirable to provide a system which can remotely reprogrammed.
In accordance with the present invention, a near object detection (NOD) system includes a plurality of radio frequency (RF) transmit receive (TR) sensor modules (or more simply xe2x80x9csensorsxe2x80x9d) disposed about a vehicle such that one or more detection zones are deployed about the vehicle. In a preferred embodiment, the sensors are disposed such that each sensor detects object in one or more coverage zones which substantially surround the vehicle. First ones or the plurality of sensors can be mounted in rear and/or front bumpers of the vehicle while second ones of the sensors can be mounted in the side panels of the vehicle. Each of the sensors includes a sensor antenna system which comprises a transmit antenna for emitting or transmitting an RF signal and a receive antenna for receiving portions of the transmitted RF signal which are intercepted by one or more objects within a field of view of the transmit antenna and reflected back toward the receive antenna. Alternatively, a monostatic antenna can be used. The transmit antenna can be provided from a planar array of antenna elements while the receive antenna can be provided from a planar array of antenna elements or from a single row of antenna elements. That is, the transmit and receive antennas can be provided having different numbers and types of antenna elements. The NOD system further includes a receiver circuit, coupled to the receive antenna, for receiving signals from the receive antenna and for determining whether an RF leakage signal coupled from the transmit antenna to the receive antenna exceeds a predetermined leakage signal threshold level.
With this particular arrangement, a NOD system which detects objects in any region about a vehicle is provided. If one the sensors determines that the vehicle is approaching an object or that an object is approaching the vehicle, then the sensor initiates steps which are carried out in accordance with a set of detection rules.
In one embodiment, the system is provided as a distributed processor system in which each of the sensors includes a processor. The sensors are each coupled together to allow the sensors to share information. In another embodiment, each of the sensors is coupled to a central sensor processor which receives information from each of the sensors and processes the information accordingly.